An Ethernet is a data link layer and physical layer technology of a packet-based network. A data link layer of the Ethernet mainly includes a Media Access Control layer (Media Access Control, MAC for short) of the Ethernet. A physical layer of the Ethernet mainly includes: a reconciliation sublayer (Reconciliation Sub-layer, RS for short), a media independent interface (Media Independent Interface, MII for short), a physical coding layer (Physical Coding Sublayer, PCS for short), a Physical Medium Attachment Sublayer (Physical Medium Attachment, PMA for short), a Physical Medium Dependent Sublayer (Physical Medium Dependent, PMD for short), an interface between a physical medium and each layer, and the like, where the RS is adaptive to the link layer and the physical layer, and provides required adaptation for the MAC and the physical layer to exchange data through the MII.
The PCS is used to encode an information group transmitted by the MIT, transmit an encoded information group to the PMA, decode the information group transmitted by the PMA, and transmit decoded information to the RS/MAC layer through the MIL
At present, the most commonly used encoding manner is a 64b/66b encoding manner. In this manner, two types of two-bit (synchronous) header information (0b10, 0b01) are used to mark two types of encoded information groups; and types of the two encoded information groups mark the (synchronous) header information into two types according to whether characters in an information group are all data characters. When an information group does not include only a data character, a control character other than the data character in the information group is compressed and encoded, and a limited combination of the data character and the control character that are in the information group is recorded by using the first byte. The encoding manner is first widely used in a 10GE, and is also applied to a 40GE and a 100GE (100 Gigabit Ethernet).
In the 10GE, the 40GE, the 100GE, and a second generation 100GE, to reduce a redundancy overhead of a (synchronous) header, a 64b/66b to 512b/513b transcoding overhead compressing technology (Trasncoding) and a 64b/66b to 256b/257b transcoding overhead compressing technology are derived based on the 64b/66b encoding.
To adapt to the development of a large-capacity high-speed Ethernet such as a new-type 100GE, a 400GE (400 Gigabit Ethernet), a 1000GE (1000 Gigabit Ethernet), new requirements such as an optimal encoding overhead proportion, low complexity and high flexibility, and high implementation efficiency are put forward on an information group encoding technology of an Ethernet physical layer.
However, the foregoing encoding manner of the Ethernet physical layer has at least the following problems: a length of a to-be-encoded information group and a redundancy overhead of a (synchronous) header cannot be flexibly selected. On the one hand, selection and use of an optimal length of an encoded information group are limited, and therefore, optimal (synchronous) header overhead control is difficult to be implemented; on the other hand, selection of matched physical layer forward error correction (Forward Error Correction, FEC for short) encoding is limited.